Unknown salivary gland target

The term 'Unknown salivary gland target' refers to a historically unidentified molecular entity or mechanism responsible for the high physiological accumulation of prostate-specific membrane antigen (PSMA)-targeted radioligands in the salivary glands. This uptake is a significant clinical challenge in the treatment of prostate cancer with therapies like Lutetium Lu 177 vipivotide tetraxetan (Pluvicto), as it leads to off-target toxicity and side effects such as xerostomia (dry mouth). While the uptake was long attributed to an 'unknown target' or non-specific excretion, recent research has identified alternative proteins, specifically N-acetylated-alpha-linked acidic dipeptidase-like 1 (NAALADL1, also known as NAALADaseL) and metabotropic glutamate receptor 8 (mGluR8), as the likely candidate molecules that bind these tracers in salivary tissues. Because the term does not refer to a single recognized canonical molecule, it is considered an ill-defined or incorrect target entry in a structured pharmacological context.

Other names

PSMA-like proteinNon-specific salivary gland targetUnidentified salivary gland uptake mechanism

Non-specific binding or off-target uptake of glutamate-ureido-lysine (GUL)-based probes